Process for obtaining color separations from multilayer photographic film



June 13, 1950 A. B. JENNINGS 2,511,112

PROCESS FOR OBTAINING COLOR SEPARATIONS FROM MULTILAYER PHOTOGRAPHIC FILM Filed Sept. 12, 1945 RE D GREEN BLUE WO H BLUE SENSITIVE El-1346K H5 m7 YELLOW FILTER A wl'yfld 6}? G RE E N EXPOSED RECORD) SENSITIVE 1N OJQAZERE JiEfl/FFILM FED RECORD RGER ESNE E 5' #185 B MHSTEJPPOSIIJVZ FROM C Wow? FILM FRO/VT FILM WITH D GREENRECORD .PE'MO l E'D .Dl/PE'NEGHTI V112 PRINTEDIROM E .SUPERMPOSED j'LI/FREwRD 27 AND MHSZZR 1 0.511! V5 "0 IN VEN TOR.

ATTORNEY Patented June 13, 1950 PnooEssroR:onrammefipi olt sEPAnA- TIoNs "FROM :MULTILAYER PHOTOI GRAPHIC FILM Andrew Bradshaw Jennings; Ne'w Brunswick, N.'J.,'assig' nor'-to E: -I. du Pont de Nemours.&.. comp'anygwilmin'gton, Del., a corporation of ---Delaware- Application September 12, 1915, Serial No. 615,773

This invention relates to: color photography and more particularly to photographic films and, processes of producing color separation-records therefrom. More particularly itrelates to =bipack photographic films, one of the film elements of which will record two different color separation records and to processes for obtaining individual color separation recordstherefrom.

An object of this invention is to..provide..new-

and useful multip ack photographic A fur--- th'er object-is toprovidebipack films for recording three-color separation records which can be utilized to readily reproduce three individual color separation records. Astill further objectit to provide a bipack film with one elementjon recording two color separation records from which one record can readily be removed in a reproduction process. Another objectis to; pro,-

vide novel: processes for obtaining color separa tion records from such a bipack. Still other objects will be apparent from the following:des'cription of the invention. n

It has been found that novel bipackphotographic films which are relatively easy to manufacture and can be readily processed to threecolor separation negatives with existingequipment and facilitiesof commercial motion picture laboratories by the followingmethods.

The front film ior'the'novel bipack'ismade' by coating a suitable film base on' one side witha water-permeable colloid-silver halide "emulsion; a layer of such a colloid free from 'light sens'itive silver salts is then. coated on the resulting layer. after it has dried, then there is coated on'the latter colloid layer, a layer of a' water-permeable colloid-silver halide emulsion. The respective silver halide layers are so disposed and/or sensitized that each is sensitive to a difie'rent primary color region of the visible spectrum. The innermost layer is generally sensitive to blue-light, whereas the outermost layer may be" sensitive, in addition, to green or redllight. A light screening dye or pigment is either placed in the innermost layer or in the intermediate layer free from silver halides. Flor example, either the blue,- sensitive layer or the screening layer contain colloidal silver and it is preferably yellow in color so that it has blue light absorption characteristios and will allow green and red light to expose the remaining layers. Other types of colloidal or inert silver may be used, however, in conjunctionwith a yellow filter dye whichrnay 'be' placed in the emulsion or separator layer.

The rear film for the novel bipacl; merely. consists of a transparent film base which carries" 'e'olaims. (01-95-2) a light-sensitive silver halide water-permeable colloid emulsion layer. The emulsion layer is sensitive to red or green light.

lnjusinglgthe film, the" two emulsion; surfaces of the frontele'ment'A and the'rear film ele- "ment B; arerplacedtsin a. camera. sothat the front filmzisrfirst exposed through the base. The two films are then de'veloped whereby three-color separation records are formed: in'the respective layers:v The: front- :film: color separation records are then":separated by. printing :a master posititle- C1 c t-both: records .as shown in Fig. 1 ofthe attaclrl'ed drawing;v The green hecord'is removed from the originalanegative :A by immersion in hot water .pr anaqueous solution: of. an alkaline thiocyanate, e. g., sodium, potassiurm-and ammonium thiocyanates; chlorohydrins, e.- g., ethylene chlorohydrins; amides, e. g., acetamide, hydroxyacetamide, etc:

"If desired a' hardening"developer solution may be'u's'ed thefiev'elopmei'it of the front-film. If anomal -developer is used-,a hardening bath can be used 'p'fior or during'the removal of the green record; After removal ofsuc-h record, the master positive"C'andthepositive blue record are super-- imposed and a'-'clupe"negative E is printedtherefrom) I In the prefei'redaspect'ofthe invention,- a novel from element'i's ma'degas shown 'in"'Fig'. '2, by'dep'ositing on a transparent film-base l a "bluesensitivegelatino silver halide emulsiomhaving dispersed thereitliroug'h yellow colloidalsilver to rorimiayeriz; Next there is co'ateda layer 3"com posed or gelati'n'iipon which is deposited anortliosensitized gelatino-silver halide'emulsion to form layer 4'. Thelfilin element just described is placed inrcoiitact with a" film elementhaving a panchromatic.-gelatino-silver' halide emulsion layer, as'des'cfibed above'and' exposed to'a color scene. The film? elements. are developed in an'ord'iiiary developerffixed, washed, and dried. A master positive Cv is then printed, as shown in Fig. 1.

The fili n element is' ithen treated "in an aqueous,

solution containing ammonium dichromate and potassium thiocyanate. They may be used in respective amounts of to 200 and 20 to. per

liter of solution. It has been found that the solution hardens the-gelatin layer containing the dispersed-si-lver butdoes not bleach the silver images. Inaddition, the solution softens the separator layer so that the-outerlayercan-more easily-be removed. Upon rinsing the film' in water, the separator layer of-plaingelatin is dissolved which permits easy removal of the outer green-sensitive layer. The surface "of the'blue-sensitive emulsion layer is substantially unaffected by the treatment which is somewhat surprising and unexpected because in the absence of the colloidal silver the surface has a relief image.

Colloidal yellow silver may be used in the gelatin separator layer if desired but when so used is not as satisfactory. It is more difiicult to remove the separator layer and outer image bearing layer. There is formed, moreover, a relief image surface on each of the emulsion layers.

The yellow colloidal silver can be made by adding solution B to A (which follow) at a temperature of 80 F. slowly with stirring:

Solution A Grams AgNOs (crystals) 20 Gelatin 150 Water 2000 Solution B Diphenyl carbazide grams 7.28 Ethanol s 723.00 NH4OH (conc.) drops 12.00

Example I A cellulose nitrate film base having a thin gelatin coating was coated with a gelatino-silver iodobromide emulsion which had admixed therewith 50% of yellow colloidal silver prepared as described above, to a weight of 52 mg. per sq. dec. After drying a gelatin solution containing 629 g. of gelatin per 15,000 g. of water was digested 15 minutes at 125 F., cooled to 100 F. and coated to form a layer .0001 inch thick. A gelatinosilver iodobromide emulsion containing 1,1-diethyl-2,2-cyanine iodide as an ortho-sensitizing dye was coated on the gelatin layer to a weight of 48 mg. per sq. dec.

was coated in like manner to form a thin antiabrasion layer. This film element constitutes the front film A of a bipack.

A similar film base was coated with an aqueous gelatin solution to a weight of 50 mg. per sq. dec. and dried. A gelatino-silver iodobromide emulsion containing as a green blind sensitizing dye 1,1-diethyl-2,4'-carbocyanine iodide was coated on the gelatin substratum. It constituted the rear film of a bipack.

The two films were placed with the gelatin layers in contact and exposed to a color scene and processed as follows:

(1) Developed for ten minutes in the following developer:

Hydroquinone grams 7.5 Metol do 5.0 Sodium sulfite (anhyd.) do 60.0 Sodium carbonate (anhyd.) do 50.0 Potassium bromide do 4.5 Water liter 1.0

(2) Fixed in the following solution and washed and dried:

A gelatin solution containing 450 g. of gelatin per 14,400 g. of water Water ccs 500 Hypo gram= 240 Sodium sulfite (anhyd.) do 0 Sodium bisulfite do 25 Water to liter 1 (3) Film A was then bleached for 5 minutes at 65 F. in a solution made by adding to 60 cc. of water cc. of Solution A and 10 cc. of Solution B which follow:

Solution A Sulfuric acid (conc.) ccs 4 Ammonium dichromate grams 15 Water to liter 1 Solution B Sodium chloride grams 45 Water to liter 1 "(4) Washed 5 minutes in hot water at 1 5 F.

whereby the gelatin separator dissolved and the green-sensitive layer was removed.

(5) Redeveloped 5 minutes in the followin developer:

Sodium sullte (anhyd.) grams 6.5 Pyro do 28.3 Potassium bromide do 6.5 Water to Men. 1.0

Sodium carbonate(monohydrate) -grams 113.4 Water to liter 1.0

. J C Sodium bisulfite grams 85.0 Water to liter 1.0

m For use take: cc. A 75 cc. B cc. H2O

Inplace of step (4) the outer layer can be removed by using any of the gelatin solubilizing agents above mentioned. For example, after developing and printing the master positive, the front film is bathed at 68 F. in a solution of ammonium thiocyanate (200 g.) in water (1 liter). The outer layer and separator soften and float away. After washing the remaining blue record is dried. The elimination of the green recordrequired only three minutes.

Example II A bipack film element as described in Example I was exposed to a color scene and the front film was processed as follows:

(1) Developed 10 minutes in:

at mare was developedand fixed-- after the manner aescribed :in steps l-) and (2) thereof. The. was then --'treatedat room tem prature:.=in =an aqueous solution containing 50 to 200 parts of ammonium dichromate and to 100 parts of potassium thiocyanate per liter, whereby the outer layer was removed and then rinsed in plain water and dried. This method eliminates redevelopment.

Example IV A photographic film as described in Example I was developed and fixed after the manner described in steps (1) and (2) thereof. was then treated in an aqueous solution containing 50 to 200 parts of ammonium dichromate per liter and next treated in an aqueous solution containing 20 to 100 parts of potassium thiocyanate whereby the outer layer was softened and removed. The film was then rinsed in water at room temperature and dried.

While the novel element containing two lightsensitive layers and a stratum of colloidal silver has been described as the front element of a bipack, it is not limited to such an arrangement but can be the rear element if desired.

An advantage of the present invention is that it enables the photographic technician to produce three-color separation negatives of high quality in a shorter time and utilizing the existing equipment and facilities of the commercial laboratory.

Another advantage resides in the fact that after the green record is removed from the front negative bipack film the blue record retains its original character, especially when the colloidal silver is disposed in such layer.

A further advantage is that photographic processing time is decreased and quality is enhanced by the simple expedient of using colloidal silver in an inner silver halide emulsion layer or a contacting light-in-sensitive water-permeable colloid layer.

The type of material lends itself to use in ordinary cine cameras with the usual bipack modifications.

The preferred aspect permits use of solutions at a normal processing temperature thereby reducing the distortion characteristic of high temperature processing.

As many widely different embodiments of this invention can be made without departing from the spirit and scope thereof, it is to be understood that the invention is not to be limited except as defined by the claims.

What is claimed is:

l. The process which comprises developing an exposed photographic element comprising a transparent film base having superimposed thereon in order a water-permeable gelatin silver halide layer which is sensitive to blue light and contains yellow colloidal silver, a water-permeable light-insensitive gelatin layer, and a water-permeable silver halide layer which ill) insensitive:toaav;diiferent: primary- .color=zofr;the visiblev-spectrhmy. fixing said: element :and v;re.--=.- moving said light-insensitive layer and outer;

light-ssensitive' layers by treatment .in.:an--aque- 1, ous bath, isaidi processbeing: further: characterizedin that .prion :to ;;remoyi-ng;: said: layfirs the lementuiszi-treated in an aqueouszbath contain-.- ing a gelatin hardening agent whieh reactsawith the colloidal silver in the blue-sensitive layer to aunif'ormly 'harden the gelatin of said layer.

2. The process whichcomprises, developing an exposed photographic element" comprising a transparentfilm basehaving superimposed there'- on in order a blue-sensitive gelatino-silvei:halidez emulsion layer containing yellow colloidal silver, a light-insensitive gelatin layer and'a gelatinosilver halide emulsion layer which is sensitive to a primary color of the visible spectrum higher than blue, fixing said element and removing said light-insensitive layer and outer light-sensitive layer by treatment in a hot aqueousybath, said process being further characterized in;;that prior to removing said layers the element is treated in an aqueous bath containing a soluble dichromate gelatin hardening agent which reacts with the colloidal silver in the blue-sensitive layer to uniformly harden the gelatin of said layer.

3. The process which comprises developing an exposed photographic element comprising a transparent film base having superimposed thereon in order a water-permeable gelatin silver halide layer which is sensitive to blue light and contains yellow colloidal silver, a water-permeable light-insensitive gelatin layer, and a waterpermeable light-insensitive colloid layer, and. a water-permeable silver halide layer which is sensitive to a primary color of the visible spectrum higher than blue, fixing said element, treating the fixed element in an aqueous solution of ammonium dichromate and potassium thiocyanate which react with the colloidal silver in the bluesensitive layer to uniformly harden the gelatin of such layer, and rinsing the treated element in water whereby the separator and outer developer layer are removed. 1""

4. The process which comprises developing an exposed photographic element comprising a transparent film base having superimposed thereon in order a water-permeable gelatin silver halide layer which is sensitive to blue light and contains yellow colloidal silver, a Water-permeable light-insensitive gelatin layer, and a waterpermeable silver halide layer which is sensitive to a primary color of the visible spectrum higher than blue, fixing said element, treating the fixed element in an aqueous solution of ammonium dichromate and then in an aqueous solution containing potassium thiocyanate which react with the colloidal silver in the blue-sensitive layer to uniformly harden the gelatin of such layer, and rinsing the treated element in water whereby the separator and outer developed layer are removed.

5. The process which comprises developing an exposed photographic element comprising a transparent film base having superimposed thereon in order a blue-sensitive gelatino-silver halide emulsion layer containing yellow colloidal silver, a light-insensitive gelatin layer, and a gelatinosilver halide emulsion layer which is sensitive to a primary color of the visible spectrum higher than blue, fixing said element, treating the fixed element in an aqueous solution of ammonium dichromate and potassium thiocyanate which react with the colloidal silver in the blue-sensitive layer to uniformly harden the gelatin of suchlayer,

the separator and outer developed layer are removed.

6. A process as set forth in claim 3 wherein the ammonium dichromate is present in an amount of 50 to 200 grams and the potassium thiocyanate is present in an amount of 20 to 100 grams per liter of solution.

, ANDREW BRADSHAW JENNINGS.

REFERENCES CITED The following references are of record in the file of this patent:

8 UNITED STATES PATENTS Number Name Date Troland Dec. 6, 1932 Lierg May 15, 1934 Eggert et a1 Apr. 11, 1939 Schinzel Sept. 5, 1939 Sease et a1 Feb. 27, 1940 Wilmanns et a1 Nov. 5, 1940 Pollak 1 May 13, 1941 Sease et a1. Nov. 11, 1941 Schinzel Dec. 16, 1941 Schinzel Sept. 8, 1942 Gaspar Apr. 20, 1943 Eggert et a1 June 1, 1943 

1. THE PROCESS WHICH COMPRISES DEVELOPING AN EXPOSED PHOTOGRAPHIC ELEMENT COMPRISING A TRANSPARENT FILM BASE HAVING SUPERIMPOSED THEREON IN ORDER A WATER-PERMEABLE GELATIN SILVER HALIDE LAYER WHICH IS SENSITIVE TO BLUE LIGHT AND CONTAINS YELLOW COLLOIDAL SILVER, A WATER-PERMEABLE LIGHT-INSENSITIVE GELATIN LAYER, AND A WATER-PERMEABLE SILVER HALIDE LAYER WHICH IS SENSITIVE TO A DIFFERENT PRIMARY COLOR OF THE VISIBLE SPECTRUM, FIXING SAID ELEMENT AND REMOVING SAID LIGHT-INSENSITIVE LAYER AND OUTER LIGHT-SENSITIVE LAYER BY TREATMENT IN AN AQUEOUS BATH, SAID PROCESS BEING FURTHER CHARACTERIZED IN THAT PRIOR TO REMOVING SAID LAYERS THE ELEMENT IS TREATED IN AN AQEOUS BATH CONTAININ A GELATIN HARDENING AGENT WHICH REACTS WITH THE COLLOIDAL SILVER IN THE BLUE-SENSITIVE LAYER TO UNIFORMLY HARDEN THE GELATIN OF SAID LAYER. 